Which of the following is considered a method of classified information disclosure?

Private conversations are considered a method of classified information disclosure when they involve discussions about sensitive information in a setting where the participants may not have the appropriate security clearances or need-to-know. This method can inadvertently lead to the dissemination of classified information if the conversation is overheard or if individuals who do not have authorization are present.

In contrast, methods like public briefings, non-secure emails, and phone calls lack the stringent controls necessary for discussing classified information. Public briefings are designed for general audiences and therefore exclude sensitive material. Non-secure emails do not provide the required protection for classified data, making them unsuitable for safe communication of such information. Phone calls, while they may offer privacy, are also not secure unless conducted over encrypted lines or within a secure environment, thus they are not inherently reliable for classified discussions.

The nature of private conversations makes them particularly vulnerable to unintentional disclosures, especially if the proper security protocols are not followed.